Conventionally, for example as described in U.S. Pat. No. 6,755,209, a flush water supply apparatus for supplying flush water into a flush water tank of a toilet has been known wherein the flush water supply apparatus adopts a structure including: a small tank which has a shape like a bucket and whose bottom surface has an opening; a float provided in the small tank; and a water supply valve movable in a horizontal direction in conjunction with a vertical movement of the float. In general, the water supply valve is a diaphragm valve.
In addition, as described in JP-A-2011-64008 and JP-A-2013-204389, another structure of the flush water supply apparatus has been known wherein the position of a small tank and the position of a float are adjustable.
FIG. 16 of the present patent application corresponds to FIG. 4 of JP-A-2013-204389 (although the numeral signs are changed). The flush water supply apparatus shown in FIG. 16 includes: a water supply valve 136 for switching between a supply (dispensing) state and a stop state of flush water supplied from a water supply pipe 134 provided with a filter 150, into a flush water tank; a small tank 138 movable in a vertical direction along the water supply pipe 134; and a float 142 provided in the small tank 138. The float 142 is slidable against the small tank 138 in a vertical direction in conjunction with a change of a flush water level in the small tank 138.
Then, a swinging member 144 (e.g. swinging arm) is provided pivotably around a fulcrum on a valve housing supported by the water supply pipe 134. When the swinging member 144 is pivoted, a pilot hole 136g is opened or closed, which causes the water supply valve 136 to switch between the supply (dispensing) state and the stop state.
The pivoting (swinging) movement of the swinging member 144 is caused by a vertical movement of the float 142. That is to say, the swinging member 144 is connected to the float 142. Herein, the swinging member 144 and the float 142 are connected via a float-position adjusting member 148 so that the relative position between the swinging member 144 and the float 142 is adjustable.
Specifically, the float-position adjusting member 148 is in general a substantially tubular member. A male threaded part is provided on an outer side surface of the float-position adjusting member 148. On the other hand, a female threaded part is provided on a portion of an inner side surface of an attachment hole formed at a center part of the float 142. Then, the male threaded part and the female threaded part are engaged to each other threadedly. Thus, when the float-position adjusting member 148 is circumferentially rotated around an axis thereof, the relative position between the float-position adjusting member 148 and the float 142 is adjusted so that the relative position between the swinging member 144 and the float 142 is adjustable.
Furthermore, a rotatable shaft member 146 extends axially through the float-position adjusting member 148. The rotatable shaft member 146 is supported by the water supply pipe 134 (in such a manner that a rotation of the rotatable shaft member 146 is allowed) so that the rotatable shaft member 146 is vertically suspended. A male threaded part is provided on an outer side surface of a lower portion of the rotatable shaft member 146. On the other hand, a female threaded part is provided on a portion of an inner side surface of an attachment hole formed at a center part of the small tank 138. Then, the male threaded part and the female threaded part are engaged to each other threadedly. Thus, when the rotatable shaft member 146 is circumferentially rotated around an axis thereof, the relative position between the rotatable shaft member 146 and the small tank 138 is adjusted (the small tank 138 is vertically moved along the water supply pipe 134).
Herein, it is not easy to directly operate the rotatable shaft member 146 because the diameter of the rotatable shaft member 146 is relatively small. Therefore, a corotation structure as shown in FIG. 17 has been adopted wherein the rotatable shaft member 146 is rotated together with the float-position adjusting member 148 when the float-position adjusting member 148 is circumferentially rotated.